A GRAPH IS USED TO CONVEY INFORMATION about statistical data. When choosing a graph, the designer must decide who their audience will be and what they are trying to show. The concepts and display of the graph must be appropriate for the intended audience. The graph format depends on the type of statistical data to be represented. 

•  Shows a whole divided into parts
• How the parts relate to each other
• How each part relates to the whole
• Use divided bar or pie graphs 
  

•  Shows how much or how many
• Used for comparison of categories
• Use visual table, line, bar, side-by-side graphs 
  

•  To illustrate changes during specified time periods
• Use when vertical axis is a continuous scale
• Not to show precise values
• Use line, stack bars, layer graphs

Tim Simmons